fish suddenly dying, any advice?

[inuchan74]

Hi all! I haven't been on here in a mighty long time and not really sure where to put this because I guess it could have gone in a few places. I've had my 20 gallon up for about a year and a half. This is what is/was in the tank:
live sand
live rock
1 clarkii clownfish
1 engineer goby
1 Dardanus spp. hermit crab (w/ 2 anemones attached to the shell)
1 red legged hermit crab
1 decorator crab
2 green chromis

Was a little concerned that the dardanus and decorator crab would clash but they completely left each other alone. Never had any problems with any of the fish or inverts, other than the clarkii was a bit territorial to his plant that he treated like an anemone. So that was the tank.

Anyways, last Tuesday the dardanus crab died. Found him half alive floating in the clarkii's plant. I thought maybe he was trying to switch shells and didn't find the other shells acceptable and started getting picked at until he couldn't be saved. I left the shell with the anemones. The SG was getting a little lower than I like so I did a partial water change Wednesday and all the levels were lookin good. I went out of town Friday and came back on Sunday morning to find the tank looking horrible. Clarkii, the goby and the decorator crab were all dead, and the water was clouded and looked terrible. I got everything cleaned up and did another partial water change because it was so scuzzy. The filter does the job but just wasn't handling it.

Both green chromises, the redleg hermit crab and the little anemones are still alive (all the cheapey things made it, of course.) I cannot figure out what happened. I tested the water again today and it's all still in acceptable ranges although all I have at the moment are those stupid dipsticks and from my understanding those aren't totally reliable. The hydrometer says the SP is 1.022. The water looks better, but still kind of hazy. We were planning on upgrading to a 40 gallon by the end of the year because I was finally feeling comfortable with maintaining this tank and we wanted to step it up and get an anemone and some frags. Now I don't know... I got the clarkii about a month after I set the tank up, and he's made it through all my trail and errors so I was just shocked that even he was gone. And upset, of course. Any ideas on what I did wrong or what I can do to keep this kind of thing from happening again?
Thanks!

 

[Smitty]

Sorry to hear that...what we're your levels at? It could be a number of things that took place over that weekend that you were gone. Temp spike, low salinity shock, low oxygen level, unknown airborne chemical that may have gotten in the tank.

 

[wontonflip]

+1 smitty

I tested the water again today and it's all still in acceptable ranges although all I have at the moment are those stupid dipsticks and from my understanding those aren't totally reliable.

You should go out and get dropper test kits (API is what I use), and get yourself a refractometer and get rid of the hydrometer, as they can be unreliable after a while. When you say your salinity was low, how low did it get and how much did you raise it by? If you raised it more than .001 in one water change, that could contribute to the stress/death. The first crab death might have been unrelated. We need more details about your setup.

Sorry to hear for your loss, though.

 

[Northstar24]

I'm with wonton here, we need more information

You've covered the inhabitants, but when you say your water parameters are 'fine' what do you mean? What are you seeing for Ammonia, Nitrite, and Nitrate

Have there been any recent changes to your setup other than the death of the crab? I highly doubt that a single crab dying would kick off a cycle, but I suppose its possible

When you were out of town, was someone feeding the tank / topping it off for evaporation? Is it possible that the tank was overfed?

Cloudy / scuzzy water could be due to some sort of bacterial bloom, but I really cant say anything for sure without more information about your setup

 

[BL1]

Definitely need to know your specific numbers. Also, when did you add the last fish to your tank? I think part of the problem may have been too many fish in a tank your size. 4 fish is a huge bioload for a 20 gallon tank to handle.

 

[wontonflip]

Cloudy / scuzzy water could be due to some sort of bacterial bloom, but I really cant say anything for sure without more information about your setup

Which could mean that there was some sort of ammonia spike, causing another cycle, which caused a bacterial bloom. And the ammonia is probably what killed the other 2 fish.

 

[Northstar24]

Which could mean that there was some sort of ammonia spike, causing another cycle, which caused a bacterial bloom. And the ammonia is probably what killed the other 2 fish.

Exactly what I was thinking, but we need more info from the OP. Someone should really sticky the template I wrote up in the 'New to Reefing' section

OP - in order to better help you with your issue, please see the template found in this thread, copy it, fill it out, and paste it in a response here
https://www.livingreefs.com/sticky-oh-noez-mah-fish-sick-threads-t34819.html

 

[inuchan74]

Thanks everyone! I looked at the Sticky and will fill definately fill it out when I get home with all the information